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Lei R, Tschopp E, Hendrickx C, Wedel MJ, Norell M, Hone DW. Bite and tooth marks on sauropod dinosaurs from the Morrison Formation. PeerJ 2023; 11:e16327. [PMID: 38025762 PMCID: PMC10655710 DOI: 10.7717/peerj.16327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 09/30/2023] [Indexed: 12/01/2023] Open
Abstract
Tooth-marked bones provide important evidence for feeding choices made by extinct carnivorous animals. In the case of the dinosaurs, most bite traces are attributed to the large and robust osteophagous tyrannosaurs, but those of other large carnivores remain underreported. Here we report on an extensive survey of the literature and some fossil collections cataloging a large number of sauropod bones (68) from the Upper Jurassic Morrison Formation of the USA that bear bite traces that can be attributed to theropods. We find that such bites on large sauropods, although less common than in tyrannosaur-dominated faunas, are known in large numbers from the Morrison Formation, and that none of the observed traces showed evidence of healing. The presence of tooth wear in non-tyrannosaur theropods further shows that they were biting into bone, but it remains difficult to assign individual bite traces to theropod taxa in the presence of multiple credible candidate biters. The widespread occurrence of bite traces without evidence of perimortem bites or healed bite traces, and of theropod tooth wear in Morrison Formation taxa suggests preferential feeding by theropods on juvenile sauropods, and likely scavenging of large-sized sauropod carcasses.
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Affiliation(s)
- Roberto Lei
- Università degli Studi di Modena e Reggio Emilia, Moderna, Italy
| | - Emanuel Tschopp
- American Museum of Natural History, New York, NY, USA
- Universität Hamburg, Hamburg, Germany
- GeoBioTec, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | | | | | - Mark Norell
- American Museum of Natural History, New York, NY, USA
| | - David W.E. Hone
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, United Kingdom
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2
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Conti S, Tschopp E, Mateus O, Zanoni A, Masarati P, Sala G. Multibody analysis and soft tissue strength refute supersonic dinosaur tail. Sci Rep 2022; 12:19245. [PMID: 36482175 PMCID: PMC9732322 DOI: 10.1038/s41598-022-21633-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 09/29/2022] [Indexed: 12/13/2022] Open
Abstract
Sauropod dinosaurs are well known for their massive sizes and long necks and tails. Among sauropods, flagellicaudatan dinosaurs are characterized by extreme tail elongation, which has led to hypotheses regarding tail function, often compared to a whip. Here, we analyse the dynamics of motion of a 3D model of an apatosaurine flagellicaudatan tail using multibody simulation and quantify the stress-bearing capabilities of the associated soft tissues. Such an elongated and slender structure would allow achieving tip velocities in the order of 30 m/s, or 100 km/h, far slower than the speed of sound, due to the combined effect of friction of the musculature and articulations, as well as aerodynamic drag. The material properties of the skin, tendons, and ligaments also support such evidence, proving that in life, the tail would not have withstood the stresses imposed by travelling at the speed of sound, irrespective of the conjectural 'popper', a hypothetical soft tissue structure analogue to the terminal portion of a bullwhip able to surpass the speed of sound.
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Affiliation(s)
- Simone Conti
- GeoBioTec, Department of Earth Sciences, NOVA School of Science and Technology, Campus de Caparica, 2829 516 Caparica, Portugal ,grid.4643.50000 0004 1937 0327Department of Aerospace Science and Technology, Politecnico di Milano, via La Masa 34, 20156 Milan, Italy
| | - Emanuel Tschopp
- GeoBioTec, Department of Earth Sciences, NOVA School of Science and Technology, Campus de Caparica, 2829 516 Caparica, Portugal ,grid.9026.d0000 0001 2287 2617Universität Hamburg, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany ,grid.241963.b0000 0001 2152 1081American Museum of Natural History, Central Park West @ 79th St, New York, NY 10024 USA
| | - Octávio Mateus
- GeoBioTec, Department of Earth Sciences, NOVA School of Science and Technology, Campus de Caparica, 2829 516 Caparica, Portugal
| | - Andrea Zanoni
- grid.4643.50000 0004 1937 0327Department of Aerospace Science and Technology, Politecnico di Milano, via La Masa 34, 20156 Milan, Italy
| | - Pierangelo Masarati
- grid.4643.50000 0004 1937 0327Department of Aerospace Science and Technology, Politecnico di Milano, via La Masa 34, 20156 Milan, Italy
| | - Giuseppe Sala
- grid.4643.50000 0004 1937 0327Department of Aerospace Science and Technology, Politecnico di Milano, via La Masa 34, 20156 Milan, Italy
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Demuth OE, Benito J, Tschopp E, Lautenschlager S, Mallison H, Heeb N, Field DJ. Topology-Based Three-Dimensional Reconstruction of Delicate Skeletal Fossil Remains and the Quantification of Their Taphonomic Deformation. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.828006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Taphonomic and diagenetic processes inevitably distort the original skeletal morphology of fossil vertebrate remains. Key aspects of palaeobiological datasets may be directly impacted by such morphological deformation, such as taxonomic diagnoses and phylogenetic hypotheses, interpretations of the shape and orientation of anatomical structures, and assessments of interspecific and intraspecific variation. In order to overcome these ubiquitous challenges we present a novel reconstruction workflow combining retopology and retrodeformation, allowing the original morphology of both symmetrically and asymmetrically damaged areas of fossils to be reconstructed. As case studies, we present idealised three-dimensional reconstructions of the sternum of the crownward stem-bird Ichthyornis dispar, and cervical vertebrae of the diplodocid sauropod Galeamopus pabsti. Multiple Ichthyornis sterna were combined into a single, idealised composite representation through superimposition and alignment of retopologised models, and this composite was subsequently retrodeformed. The Galeamopus vertebrae were individually retrodeformed and symmetrised. Our workflow enabled us to quantify deformation of individual specimens with respect to our reconstructions, and to characterise global and local taphonomic deformation. Our workflow can be integrated with geometric morphometric approaches to enable quantitative morphological comparisons among multiple specimens, as well as quantitative interpolation of “mediotypes” of serially homologous elements such as missing vertebrae, haemal arches, or ribs.
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Wencker LCM, Tschopp E, Villa A, Augé ML, Delfino M. Phylogenetic value of jaw elements of lacertid lizards (Squamata: Lacertoidea): a case study with Oligocene material from France. Cladistics 2021; 37:765-802. [PMID: 34841590 DOI: 10.1111/cla.12460] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/05/2021] [Indexed: 11/26/2022] Open
Abstract
Several extinct species are known from the family Lacertidae, but due to poor preservation, many of them are based on single bones. Here, we compare phylogenetic signals of disarticulated premaxillae, maxillae and dentaries of lacertids from four French Oligocene localities (Coderet, La Colombière, Roqueprune 2, Mas de Got B). We identified five morphotypes among the premaxillae, six among the maxillae, and ten among the dentaries. These morphotypes were scored as individual taxa per locality into three separate character matrices with the same 246 characters, one matrix for each jaw element. Subsequently, the phylogenetic position of the morphotypes was tested using maximum parsimony. The consensus trees with the dentaries and the maxillae found a large polytomy including all taxa except the outgroup taxon Gekko gecko. The consensus tree with the premaxillae showed a considerably more resolved topology but found all morphotype taxa outside Lacertidae. In a second step, we compared the constitution of our three datasets and the morphotype taxa. Our results suggest that a combination of convergent characters and missing data led to the outgroup position of the premaxilla morphotype taxa. The poor resolution of the maxillae strict consensus is likely a consequence of their fragmentary preservation. For the dentaries, a high amount of missing data due to the high number of morphotype taxa most likely caused the poor tree resolution. Indeed, tests with fewer morphotypes found tree resolutions comparable to the premaxilla data. When linking the morphotypes, five possible lacertid "species" were found. Comparison with already known French Oligocene lacertid species points to a slightly higher species richness of Lacertidae at that time than known before. Reliable species classification based on phylogeny only seems possible when combining the jaw elements or in association with other cranial and postcranial material, putting some doubt on species identifications based on single bones.
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Affiliation(s)
| | - Emanuel Tschopp
- Dipartimento di Scienze della Terra, Università degli Studi di Torino, Via Valperga Caluso, 35, Turin, 10125, Italy.,Centrum für Naturkunde, Universität Hamburg, Martin-Luther-King-Platz 3, Hamburg, 20146, Germany.,Division of Paleontology, American Museum of Natural History, Central Park West & 79th Street, New York, NY, 10024, USA
| | - Andrea Villa
- Dipartimento di Scienze della Terra, Università degli Studi di Torino, Via Valperga Caluso, 35, Turin, 10125, Italy.,SNSB-Bayerische Staatssammlung für Paläontologie und Geologie, Richard-Wagner-Straße 10, Munich, 80333, Germany
| | - Marc Louis Augé
- CR2P, UMR 7207 CNRS, MNHN, Muséum National d'Histoire naturelle, 57 rue Cuvier, Paris, 75231, France
| | - Massimo Delfino
- Dipartimento di Scienze della Terra, Università degli Studi di Torino, Via Valperga Caluso, 35, Turin, 10125, Italy.,Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Edifici ICTA-ICP, Carrer de les Columnes s/n, Campus de la UAB, Cerdanyola del Vallès, Barcelona, 08193, Spain
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Tschopp E, Napoli JG, Wencker LCM, Delfino M, Upchurch P. How to Render Species Comparable Taxonomic Units Through Deep Time: a Case Study on Intraspecific Osteological Variability in Extant and Extinct Lacertid Lizards. Syst Biol 2021; 71:875-900. [PMID: 34605923 DOI: 10.1093/sysbio/syab078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 09/16/2021] [Accepted: 09/23/2021] [Indexed: 11/13/2022] Open
Abstract
Generally, the species is considered to be the only naturally occurring taxon. However, species recognised and defined using different species delimitation criteria cannot readily be compared, impacting studies of biodiversity through Deep Time. This comparability issue is particularly marked when comparing extant with extinct species, because the only available data for species delimitation in fossils is derived from their preserved morphology, which is generally restricted to osteology in vertebrates. Here, we quantify intraspecific, intrageneric, and intergeneric osteological variability in extant species of lacertid lizards using pairwise dissimilarity scores based on a dataset of 253 discrete osteological characters for 99 specimens referred to 24 species. Variability is always significantly lower intraspecifically than between individuals belonging to distinct species of a single genus, which is in turn significantly lower than intergeneric variability. Average values of intraspecific variability and associated standard deviations are consistent (with few exceptions), with an overall average within a species of 0.208 changes per character scored. Application of the same methods to six extinct lacertid species (represented by 40 fossil specimens) revealed that intraspecific osteological variability is inconsistent, which can at least in part be attributed to different researchers having unequal expectations of the skeletal dissimilarity within species units. Such a divergent interpretation of intraspecific and interspecific variability among extant and extinct species reinforces the incomparability of the species unit. Lacertidae is an example where extant species recognised and defined based on a number of delimitation criteria show comparable and consistent intraspecific osteological variability. Here, as well as in equivalent cases, application of those skeletal dissimilarity values to palaeontological species delimitation potentially provides a way to ameliorate inconsistencies created by the use of morphology to define species.
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Affiliation(s)
- Emanuel Tschopp
- Universität Hamburg, Hamburg, Germany.,Division of Paleontology, American Museum of Natural History, New York, USA.,Dipartimento di Scienze della Terra, Università di Torino, Italy.,GeoBioTec, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - James G Napoli
- Division of Paleontology, American Museum of Natural History, New York, USA.,Richard Gilder Graduate School, American Museum of Natural History, New York, USA
| | | | - Massimo Delfino
- Dipartimento di Scienze della Terra, Università di Torino, Italy.,Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Paul Upchurch
- Department of Earth Sciences, University College London, London, UK
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Yu C, Jiangzuo Q, Tschopp E, Wang H, Norell M. Information in morphological characters. Ecol Evol 2021; 11:11689-11699. [PMID: 34522333 PMCID: PMC8427622 DOI: 10.1002/ece3.7874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/09/2021] [Accepted: 06/11/2021] [Indexed: 11/17/2022] Open
Abstract
The construction of morphological character matrices is central to paleontological systematic study, which extracts paleontological information from fossils. Although the word information has been repeatedly mentioned in a wide array of paleontological systematic studies, its meaning has rarely been clarified nor specifically defined. It is important, however, to establish a standard to measure paleontological information because fossils are hardly complete, rendering the recognition of homologous and homoplastic structures difficult. Here, based on information theory, we show the deep connections between paleontological systematic study and communication system engineering. Information is defined as the decrease of uncertainty and it is the information in morphological characters that allows distinguishing operational taxonomic units (OTUs) and reconstructing evolutionary history. We propose that concepts in communication system engineering such as source coding and channel coding, correspond to the construction of diagnostic features and the entire character matrices in paleontological studies. The two coding strategies should be distinguished following typical communication system engineering, because they serve dual purposes. With character matrices from six different vertebrate groups, we analyzed their information properties including source entropy, mutual information, and channel capacity. Estimation of channel capacity shows character saturation of all matrices in transmitting paleontological information, indicating that, due to the presence of noise, oversampling characters not only increases the burden in character scoring, but also may decrease quality of matrices. We further test the use of information entropy, which measures how informative a variable is, as a character weighting criterion in parsimony-based systematic studies. The results show high consistency with existing knowledge with both good resolution and interpretability.
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Affiliation(s)
- Congyu Yu
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNYUSA
- Department of Earth and Environmental SciencesColumbia UniversityNew YorkNYUSA
| | - Qigao Jiangzuo
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNYUSA
- Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of SciencesInstitute of Vertebrate Paleontology and PaleoanthropologyChinese Academy of SciencesBeijingChina
- Key Laboratory of Orogenic Belts and Crustal EvolutionSchool of Earth and Space SciencesPeking UniversityBeijingChina
- CAS Center for Excellence in Life and PaleoenvironmentBeijingChina
| | - Emanuel Tschopp
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNYUSA
- Center of Natural HistoryUniversity of HamburgHamburgGermany
| | - Haibing Wang
- Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of SciencesInstitute of Vertebrate Paleontology and PaleoanthropologyChinese Academy of SciencesBeijingChina
- CAS Center for Excellence in Life and PaleoenvironmentBeijingChina
| | - Mark Norell
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNYUSA
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7
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Mannion PD, Tschopp E, Whitlock JA. Anatomy and systematics of the diplodocoid Amphicoelias altus supports high sauropod dinosaur diversity in the Upper Jurassic Morrison Formation of the USA. R Soc Open Sci 2021; 8:210377. [PMID: 34150318 PMCID: PMC8206699 DOI: 10.1098/rsos.210377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 05/26/2021] [Indexed: 05/11/2023]
Abstract
Sauropod dinosaurs were an abundant and diverse component of the Upper Jurassic Morrison Formation of the USA, with 24 currently recognized species. However, some authors consider this high diversity to have been ecologically unviable and the validity of some species has been questioned, with suggestions that they represent growth series (ontogimorphs) of other species. Under this scenario, high sauropod diversity in the Late Jurassic of North America is greatly overestimated. One putative ontogimorph is the enigmatic diplodocoid Amphicoelias altus, which has been suggested to be synonymous with Diplodocus. Given that Amphicoelias was named first, it has priority and thus Diplodocus would become its junior synonym. Here, we provide a detailed re-description of A. altus in which we restrict it to the holotype individual and support its validity, based on three autapomorphies. Constraint analyses demonstrate that its phylogenetic position within Diplodocoidea is labile, but it seems unlikely that Amphicoelias is synonymous with Diplodocus. As such, our re-evaluation also leads us to retain Diplodocus as a distinct genus. There is no evidence to support the view that any of the currently recognized Morrison sauropod species are ontogimorphs. Available data indicate that sauropod anatomy did not dramatically alter once individuals approached maturity. Furthermore, subadult sauropod individuals are not prone to stemward slippage in phylogenetic analyses, casting doubt on the possibility that their taxonomic affinities are substantially misinterpreted. An anatomical feature can have both an ontogenetic and phylogenetic signature, but the former does not outweigh the latter when other characters overwhelmingly support the affinities of a taxon. Many Morrison Formation sauropods were spatio-temporally and/or ecologically separated from one another. Combined with the biases that cloud our reading of the fossil record, we contend that the number of sauropod dinosaur species in the Morrison Formation is currently likely to be underestimated, not overestimated.
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Affiliation(s)
- Philip D. Mannion
- Department of Earth Sciences, University College London, London WC1E 6BT, UK
| | - Emanuel Tschopp
- Centrum für Naturkunde, Universität Hamburg, 20146 Hamburg, Germany
- Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA
| | - John A. Whitlock
- Department of Science and Mathematics, Mount Aloysius College, Cresson, PA 16630-1999, USA
- Section of Vertebrate Paleontology, Carnegie Museum of Natural History, Pittsburgh, PA 15213-4007, USA
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9
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Seghetti SM, Villa A, Tschopp E, Bernardini F, Laddaga L, Fanelli M, Levi R, Delfino M. Skull osteology of Vipera walser (Squamata, Viperidae): Description, variability, ontogeny, and diagnostic characters in comparison to other Italian vipers. J Morphol 2020; 282:5-47. [PMID: 33058241 DOI: 10.1002/jmor.21279] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 08/24/2020] [Accepted: 09/26/2020] [Indexed: 11/09/2022]
Abstract
Vipera walser is the most recently recognized European viper. This rare species is endemic to a small area in the Piedmont Alps of Italy, but its closest relatives are found among the Caucasian viper species. In order to provide a starting point for a phylogenetic and biogeographic investigation based on osteology, and including fossils remains, we analyzed four specimens of V. walser and compared them with specimens of the four other Italian viper species. Based on these specimens, we improved the diagnosis of V. walser and provided a first evaluation of intraspecific variability and ontogenetic variation. The skull of V. walser is subject to significant variation, most likely related to ontogeny in some cases (i.e., development of the parietal crest, development of the basioccipital process, shape of the posterior margin of the parabasisphenoid, shape of the quadrate). Based on the studied material, it is possible to distinguish V. walser from the other Italian vipers by the shape of the occipital crest of the supraoccipital, which is posteriorly directed, whereas it is laterally directed in the other species. The osteological diagnosibility provides further support for the validity of V. walser as a distinct species from Vipera berus.
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Affiliation(s)
| | - Andrea Villa
- Dipartimento di Scienze della Terra, Università di Torino, Torino, Italy.,Bayerische Staatssammlung für Paläontologie und Geologie, Munich, Germany
| | - Emanuel Tschopp
- Dipartimento di Scienze della Terra, Università di Torino, Torino, Italy.,Division of Paleontology, American Museum of Natural History, New York City, New York, USA.,Centrum für Naturkunde, University of Hamburg, Hamburg, Germany
| | - Federico Bernardini
- Centro Fermi, Museo Storico della Fisica e Centro di Studi e Ricerche "Enrico Fermi", Rome, Italy.,Multidisciplinary Laboratory, The "Abdus Salam" International Centre for Theoretical Physics, Trieste, Italy
| | - Lorenzo Laddaga
- Società di Scienze Naturali del Verbano Cusio Ossola, Museo di Scienze Naturali Collegio Mellerio Rosmini, Domodossola, Italy
| | - Mauro Fanelli
- Dipartimento di Scienze della Terra, Università di Torino, Torino, Italy
| | - Renzo Levi
- Dipartimento di Scienze della Vita e Biologia dei Sistemi, Università di Torino, Torino, Italy
| | - Massimo Delfino
- Dipartimento di Scienze della Terra, Università di Torino, Torino, Italy.,Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Barcelona, Spain
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Tschopp E, Mehling C, Norell MA. Reconstructing the Specimens and History of Howe Quarry (Upper Jurassic Morrison Formation; Wyoming). American Museum Novitates 2020. [DOI: 10.1206/3956.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Emanuel Tschopp
- Division of Paleontology, American Museum of Natural History, New York
| | - Carl Mehling
- Division of Paleontology, American Museum of Natural History, New York
| | - Mark A. Norell
- Division of Paleontology, American Museum of Natural History, New York
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Tschopp E, Maidment SC, Lamanna MC, Norell MA. Reassessment of a Historical Collection of Sauropod Dinosaurs from the Northern Morrison Formation of Wyoming, with Implications for Sauropod Biogeography. Bulletin of the American Museum of Natural History 2019. [DOI: 10.1206/0003-0090.437.1.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Emanuel Tschopp
- American Museum of Natural History, Division of Paleontology, New York; Museu da Lourinhã, Lourinhã, Portugal
| | | | - Matthew C. Lamanna
- Section of Vertebrate Paleontology, Carnegie Museum of Natural History, Pittsburgh
| | - Mark A. Norell
- American Museum of Natural History, Division of Paleontology, New York
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12
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Rio JP, Mannion PD, Tschopp E, Martin JE, Delfino M. Reappraisal of the morphology and phylogenetic relationships of the alligatoroid crocodilian Diplocynodon hantoniensis from the late Eocene of the United Kingdom. Zool J Linn Soc 2019. [DOI: 10.1093/zoolinnean/zlz075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Rio JP, Mannion PD, Tschopp E, Martin JE, Delfino M. Reappraisal of the morphology and phylogenetic relationships of the alligatoroid crocodylian Diplocynodon hantoniensis from the late Eocene of the United Kingdom. Zool J Linn Soc 2019. [DOI: 10.1093/zoolinnean/zlz034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
AbstractDiplocynodon is a genus of basal alligatoroid comprising nine species, which spanned the late Palaeocene to middle Miocene of Europe. Despite recent revisions of most Diplocynodon species, one of the earliest named and most complete, Diplocynodon hantoniensis, has not been re-described for over 150 years. This species is known from the remains of numerous individuals from the Priabonian (late Eocene) Headon Hill Formation, which crops out at Hordle (Hordwell) Cliff in Hampshire, United Kingdom. Here we re-describe and diagnose Diplocynodon hantoniensis, providing the first detailed description of postcranial anatomy in Diplocynodon, and indeed any basal alligatoroid. Diplocynodon hantoniensis is diagnosed by four autapomorphies, including retention of the ectopterygoid–pterygoid flexure through ontogeny and a unique anterior process of the ectopterygoid adjacent to the posteriormost maxillary alveoli. A critical review of previously referred remains from elsewhere in Europe and the USA restricts Diplocynodon hantoniensis to the late Eocene of the UK. Through comparisons with extant crocodylians, the well-preserved postcranial skeleton enables the interpretation of numerous muscle attachments in the forelimbs and hindlimbs, providing a potentially rich source of character data for future phylogenetic analyses. Based on a comparison of humeral morphology between a large sample of crocodylian species, we outline two new morphological characters in the humerus. We include D. hantoniensis in a phylogenetic analysis, including all putative Diplocynodon species (103 taxa scored for 187 characters). We use four different character-weighting schemes: equal weighting, implied weighting (k value = 8) and extended implied weighting with k-values of 4 and 8. In general, these weighted analyses produce congruent results with the equal-weights analysis, and increase the resolution within Diplocynodon. We recover a monophyletic Diplocynodon in three of the four analyses. However, the fourth analysis, with the strongest downweighting of homoplastic characters and missing data (extended implied weighting with k = 4), recovers the Palaeocene Diplocynodon remensis outside Diplocynodon. Our comprehensive revision of one of the most completely known Diplocynodon species facilitates comparisons in the genus, as well as between other basal alligatoroids, and forms the basis for comparing postcranial anatomy in other fossil crocodylians.
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Affiliation(s)
- Jonathan P Rio
- Department of Earth Science and Engineering, Imperial College London, London, UK
| | - Philip D Mannion
- Department of Earth Sciences, University College London, London, UK
| | - Emanuel Tschopp
- Division of Paleontology, American Museum of Natural History, New York, USA
| | - Jeremy E Martin
- Université Lyon, ENS de Lyon, Université Lyon 1, CNRS, UMR 5276 Laboratoire de Géologie de Lyon: Terre, Planète, Environnement, Lyon, France
| | - Massimo Delfino
- Dipartimento di Scienze della Terra, Università di Torino, Torino, Italy
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Edifici ICTAICP, Carrer de les Columnes s/n, Campus de la UAB, Barcelona, Spain
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Tschopp E, Mateus O, Norell M. Complex Overlapping Joints between Facial Bones Allowing Limited Anterior Sliding Movements of the Snout in Diplodocid Sauropods. American Museum Novitates 2018. [DOI: 10.1206/3911.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Emanuel Tschopp
- American Museum of Natural History, Division of Paleontology, New York
- GeoBioTec, Faculdade de Ciências e Tecnologia, Universidae Nova de Lisboa, Caparica, Portugal
- Museu da Lourinhã, Lourinhã, Portugal
| | - Octávio Mateus
- American Museum of Natural History, Division of Paleontology, New York
- GeoBioTec, Faculdade de Ciências e Tecnologia, Universidae Nova de Lisboa, Caparica, Portugal
- Museu da Lourinhã, Lourinhã, Portugal
| | - Mark Norell
- American Museum of Natural History, Division of Paleontology, New York
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Maltese A, Tschopp E, Holwerda F, Burnham D. The real Bigfoot: a pes from Wyoming, USA is the largest sauropod pes ever reported and the northern-most occurrence of brachiosaurids in the Upper Jurassic Morrison Formation. PeerJ 2018; 6:e5250. [PMID: 30065867 PMCID: PMC6063209 DOI: 10.7717/peerj.5250] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 06/25/2018] [Indexed: 11/24/2022] Open
Abstract
A set of associated left pedal elements of a sauropod dinosaur from the Upper Jurassic Morrison Formation in Weston County, Wyoming, is described here. Several camarasaurids, a nearly complete small brachiosaur, and a small diplodocid have been found at this locality, but none match the exceptionally large size of the pedal elements. Next to the associated pedal elements, an isolated astragalus, phalanx and ungual were found, which match the large metatarsals in size. The elements cannot be ascribed to diplodocids due to the lack of a ventral process of metatarsal I. Moreover, the morphology of metatarsal V has a broad proximal end, with a long and narrow distal shaft, which differs from Camarasaurus. The size of the material and a medially beveled distal articular surface of metatarsal IV imply an identification as a brachiosaurid. This is the largest pes ever reported from a sauropod dinosaur and represents the first confirmed pedal brachiosaur elements from the Late Jurassic of North America. Furthermore, this brachiosaur material (the pes and the small nearly complete specimen) is the northernmost occurrence of brachiosaurids in the Morrison Formation.
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Affiliation(s)
- Anthony Maltese
- Rocky Mountain Dinosaur Resource Center, Woodland Park, CO, United States of America
| | - Emanuel Tschopp
- Division of Paleontology, American Museum of Natural History, New York, NY, United States of America.,GeoBioTec, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal.,Museu da Lourinhã, Lourinhã, Portugal
| | - Femke Holwerda
- GeoBioTec, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal.,Bayerische Staatssammlung für Paläontologie und Geologie, Staatliche Naturwissenschaftliche Sammlungen Bayerns (SNSB), München, Germany.,Department of Earth Sciences, Utrecht University, Utrecht, Netherlands
| | - David Burnham
- Biodiversity Institute, University of Kansas, Lawrence, KS, United States of America
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Tschopp E, Villa A, Camaiti M, Ferro L, Tuveri C, Rook L, Arca M, Delfino M. The first fossils of Timon (Squamata: Lacertinae) from Sardinia (Italy) and potential causes for its local extinction in the Pleistocene. Zool J Linn Soc 2018. [DOI: 10.1093/zoolinnean/zly003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Emanuel Tschopp
- Dipartimento di Scienze della Terra, Università di Torino, Torino, Italy
- Division of Paleontology, American Museum of Natural History, New York City, NY, USA
- Museu da Lourinhã, Lourinhã, Portugal
| | - Andrea Villa
- Dipartimento di Scienze della Terra, Università di Torino, Torino, Italy
| | - Marco Camaiti
- Dipartimento di Scienze della Terra, Università di Torino, Torino, Italy
| | - Letizia Ferro
- Dipartimento di Scienze della Terra, Università di Torino, Torino, Italy
| | - Caterinella Tuveri
- Soprintendenza Archeologia, Belle Arti e Paesaggio per le prov. di Sassari e Nuoro, Nuoro, Italy
| | - Lorenzo Rook
- Dipartimento di Scienze della Terra, Università di Firenze, Firenze, Italy
| | - Marisa Arca
- Soprintendenza Archeologia, Belle Arti e Paesaggio per le prov. di Sassari e Nuoro, Nuoro, Italy
| | - Massimo Delfino
- Dipartimento di Scienze della Terra, Università di Torino, Torino, Italy
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Edifici ICTA-ICP, Cerdanyola del Vallès, Barcelona, Spain
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Tschopp E, Tschopp FA, Mateus O. Overlap Indices: Tools to quantify the amount of anatomical overlap among groups of incomplete terminal taxa in phylogenetic analyses. ACTA ZOOL-STOCKHOLM 2017. [DOI: 10.1111/azo.12202] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Emanuel Tschopp
- Dipartimento di Scienze della Terra; Università degli Studi di Torino; Torino Italy
- GeoBioTec; Departamento de Ciências da Terra; Faculdade de Ciências e Tecnologia; Universidade Nova de Lisboa; Caparica Portugal
- Museu da Lourinhã; Lourinhã Portugal
| | | | - Octávio Mateus
- GeoBioTec; Departamento de Ciências da Terra; Faculdade de Ciências e Tecnologia; Universidade Nova de Lisboa; Caparica Portugal
- Museu da Lourinhã; Lourinhã Portugal
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Tschopp E, Mateus O. Osteology of Galeamopus pabsti sp. nov. (Sauropoda: Diplodocidae), with implications for neurocentral closure timing, and the cervico-dorsal transition in diplodocids. PeerJ 2017; 5:e3179. [PMID: 28480132 PMCID: PMC5417106 DOI: 10.7717/peerj.3179] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 03/14/2017] [Indexed: 11/20/2022] Open
Abstract
Diplodocids are among the best known sauropod dinosaurs. Numerous specimens of currently 15 accepted species belonging to ten genera have been reported from the Late Jurassic to Early Cretaceous of North and South America, Europe, and Africa. The highest diversity is known from the Upper Jurassic Morrison Formation of the western United States: a recent review recognized 12 valid, named species, and possibly three additional, yet unnamed ones. One of these is herein described in detail and referred to the genus Galeamopus. The holotype specimen of Galeamopus pabsti sp. nov., SMA 0011, is represented by material from all body parts but the tail, and was found at the Howe-Scott Quarry in the northern Bighorn Basin in Wyoming, USA. Autapomorphic features of the new species include a horizontal canal on the maxilla that connects the posterior margin of the preantorbital and the ventral margin of the antorbital fenestrae, a vertical midline groove marking the sagittal nuchal crest, the presence of a large foramen connecting the postzygapophyseal centrodiapophyseal fossa and the spinopostzygapophyseal fossa of mid- and posterior cervical vertebrae, a very robust humerus, a laterally placed, rugose tubercle on the concave proximal portion of the anterior surface of the humerus, a relatively stout radius, the absence of a distinct ambiens process on the pubis, and a distinctly concave posteroventral margin of the ascending process of the astragalus. In addition to the holotype specimen SMA 0011, the skull USNM 2673 can also be referred to Galeamopus pabsti. Histology shows that the type specimen SMA 0011 is sexually mature, although neurocentral closure was not completed at the time of death. Because SMA 0011 has highly pneumatized cervical vertebrae, the development of the lamination appears a more important indicator for individual age than neurocentral fusion patterns. SMA 0011 is one of very few sauropod specimens that preserves the cervico-dorsal transition in both vertebrae and ribs. The association of ribs with their respective vertebrae shows that the transition between cervical and dorsal vertebrae is significantly different in Galeamopus pabsti than in Diplodocus carnegii or Apatosaurus louisae, being represented by a considerable shortening of the centra from the last cervical to the first dorsal vertebra. Diplodocids show a surprisingly high diversity in the Morrison Formation. This can possibly be explained by a combination of geographical and temporal segregation, and niche partitioning.
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Affiliation(s)
- Emanuel Tschopp
- Dipartimento di Scienze della Terra, Università di Torino, Torino, Italy
- GeoBioTec, Faculdade de Ciencia e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
- Museu da Lourinhã, Lourinhã, Portugal
| | - Octávio Mateus
- GeoBioTec, Faculdade de Ciencia e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
- GeoBioTec + Departamento de Ciências da Terra, Faculdade de Ciencia e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
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Abstract
The capability of palaeontologists to identify fossil remains of a particular group of vertebrates strongly depends on the knowledge they have of its comparative osteology and on the actual presence of diagnostic differences among the considered taxa. This could have a relevant influence on the study of palaeodiversity, since a low recognisability causes a loss of data when trying to reconstruct the history of taxa that lived on Earth in the past. Currently, more than 6000 extant species of lizards and worm lizards are known, and new ones continue to be discovered, mainly based on molecular data. But are we able to recognise this high diversity using osteology? As far as European taxa are concerned, the osteological recognisability of non-snake squamates is very low: only 31% of the extant European taxa can be identified based on their skeletal morphology. This is balanced partially by the fact that most recognisable taxa have been actually recognised in the fossil record, suggesting that the lost data are mainly due to the scarce knowledge of the comparative osteology of these reptiles and less influenced by other biases, such as taphonomic or collection biases. In this context, specimen-level phylogenetic analysis has proved to be a useful tool to identify diagnostic combinations of osteological features, at least for lacertid species, as evidenced by a case study focused on the genusLacerta.
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Affiliation(s)
- Andrea Villa
- Dipartimento di Scienze della Terra, Università degli Studi di Torino, via Valperga Caluso 35, 10125 Torino, Italy
| | - Emanuel Tschopp
- Dipartimento di Scienze della Terra, Università degli Studi di Torino, via Valperga Caluso 35, 10125 Torino, Italy
- GeoBioTec, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
- Museu da Lourinhã, Rua João Luís de Moura, 2530-157 Lourinhã, Portugal
| | - Georgios L. Georgalis
- Department of Geosciences, University of Fribourg/Freiburg, Chemin du Musée 6, 1700 Fribourg, Switzerland
- Dipartimento di Scienze della Terra, Università degli Studi di Torino, via Valperga Caluso 35, 10125 Torino, Italy
| | - Massimo Delfino
- Dipartimento di Scienze della Terra, Università degli Studi di Torino, via Valperga Caluso 35, 10125 Torino, Italy
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Edifici ICTA-ICP, Carrer de les Columnes s/n, Campus de la UAB, 08193 Cerdanyola del Vallès, Barcelona, Spain
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Tschopp E. Nomenclature of Vertebral Laminae in Lizards, with Comments on Ontogenetic and Serial Variation in Lacertini (Squamata, Lacertidae). PLoS One 2016; 11:e0149445. [PMID: 26907769 PMCID: PMC4764367 DOI: 10.1371/journal.pone.0149445] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 02/01/2016] [Indexed: 11/19/2022] Open
Abstract
Vertebral laminae are bony ridges or sheets that connect important morphological landmarks on the vertebrae, like diapophyses or zygapophyses. They usually exhibit some serial variation throughout the column. A consistent terminology facilitates the morphological description of this variation, and the recognition of patterns that could be taxonomically significant and could serve as phylogenetic characters. Such a terminology was designed for saurischian dinosaurs, and has also been applied to other members of Archosauriformes. Herein, this terminology is applied for the first time to lizards (Squamata). Probably due to their generally smaller size compared to saurischian dinosaurs, lizards have less developed vertebral laminae. Some laminae could not be recognized in this group and others require new names to account for differences in basic vertebral morphology. For instance, the fusion of diapophysis and parapophysis in lacertids into a structure called synapophysis necessitates the creation of the new term synapophyseal laminae for both diapophyseal and parapophyseal laminae. An assessment of occurrence and serial variation in a number of lacertid species shows that some laminae develop throughout ontogeny or only occur in large-sized species, whereas the distribution of other laminae might prove to be taxonomically significant in future.
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Affiliation(s)
- Emanuel Tschopp
- Dipartimento di Scienze della Terra, Università di Torino, Torino, Italy
- GeoBioTec, Faculdade de Ciências e Tecnologia (FCT), Universidade Nova de Lisboa, Caparica, Portugal
- Museu da Lourinhã, Lourinhã, Portugal
- * E-mail:
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Tschopp E, Mateus O, Benson RB. A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda). PeerJ 2015; 3:e857. [PMID: 25870766 PMCID: PMC4393826 DOI: 10.7717/peerj.857] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 03/05/2015] [Indexed: 11/24/2022] Open
Abstract
Diplodocidae are among the best known sauropod dinosaurs. Several species were described in the late 1800s or early 1900s from the Morrison Formation of North America. Since then, numerous additional specimens were recovered in the USA, Tanzania, Portugal, and Argentina, as well as possibly Spain, England, Georgia, Zimbabwe, and Asia. To date, the clade includes about 12 to 15 nominal species, some of them with questionable taxonomic status (e.g., 'Diplodocus' hayi or Dyslocosaurus polyonychius), and ranging in age from Late Jurassic to Early Cretaceous. However, intrageneric relationships of the iconic, multi-species genera Apatosaurus and Diplodocus are still poorly known. The way to resolve this issue is a specimen-based phylogenetic analysis, which has been previously implemented for Apatosaurus, but is here performed for the first time for the entire clade of Diplodocidae. The analysis includes 81 operational taxonomic units, 49 of which belong to Diplodocidae. The set of OTUs includes all name-bearing type specimens previously proposed to belong to Diplodocidae, alongside a set of relatively complete referred specimens, which increase the amount of anatomically overlapping material. Non-diplodocid outgroups were selected to test the affinities of potential diplodocid specimens that have subsequently been suggested to belong outside the clade. The specimens were scored for 477 morphological characters, representing one of the most extensive phylogenetic analyses of sauropod dinosaurs. Character states were figured and tables given in the case of numerical characters. The resulting cladogram recovers the classical arrangement of diplodocid relationships. Two numerical approaches were used to increase reproducibility in our taxonomic delimitation of species and genera. This resulted in the proposal that some species previously included in well-known genera like Apatosaurus and Diplodocus are generically distinct. Of particular note is that the famous genus Brontosaurus is considered valid by our quantitative approach. Furthermore, "Diplodocus" hayi represents a unique genus, which will herein be called Galeamopus gen. nov. On the other hand, these numerical approaches imply synonymization of "Dinheirosaurus" from the Late Jurassic of Portugal with the Morrison Formation genus Supersaurus. Our use of a specimen-, rather than species-based approach increases knowledge of intraspecific and intrageneric variation in diplodocids, and the study demonstrates how specimen-based phylogenetic analysis is a valuable tool in sauropod taxonomy, and potentially in paleontology and taxonomy as a whole.
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Affiliation(s)
- Emanuel Tschopp
- GeoBioTec, Faculdade de Ciência e Tecnologia, Universidade Nova de Lisboa, Monte de Caparica, Portugal
- Museu da Lourinhã, Lourinhã, Portugal
- Dipartimento di Scienze della Terra, Università di Torino, Italy
| | - Octávio Mateus
- GeoBioTec, Faculdade de Ciência e Tecnologia, Universidade Nova de Lisboa, Monte de Caparica, Portugal
- Museu da Lourinhã, Lourinhã, Portugal
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Tschopp E, Mateus O. Clavicles, interclavicles, gastralia, and sternal ribs in sauropod dinosaurs: new reports from diplodocidae and their morphological, functional and evolutionary implications. J Anat 2013; 222:321-40. [PMID: 23190365 PMCID: PMC3582252 DOI: 10.1111/joa.12012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/18/2012] [Indexed: 11/28/2022] Open
Abstract
Ossified gastralia, clavicles and sternal ribs are known in a variety of reptilians, including dinosaurs. In sauropods, however, the identity of these bones is controversial. The peculiar shapes of these bones complicate their identification, which led to various differing interpretations in the past. Here we describe different elements from the chest region of diplodocids, found near Shell, Wyoming, USA. Five morphotypes are easily distinguishable: (A) elongated, relatively stout, curved elements with a spatulate and a bifurcate end resemble much the previously reported sauropod clavicles, but might actually represent interclavicles; (B) short, L-shaped elements, mostly preserved as a symmetrical pair, probably are the real clavicles, as indicated by new findings in diplodocids; (C) slender, rod-like bones with rugose ends are highly similar to elements identified as sauropod sternal ribs; (D) curved bones with wide, probably medial ends constitute the fourth morphotype, herein interpreted as gastralia; and (E) irregularly shaped elements, often with extended rugosities, are included into the fifth morphotype, tentatively identified as sternal ribs and/or intercostal elements. To our knowledge, the bones previously interpreted as sauropod clavicles were always found as single bones, which sheds doubt on the validity of their identification. Various lines of evidence presented herein suggest they might actually be interclavicles - which are single elements. This would be the first definitive evidence of interclavicles in dinosauromorphs. Previously supposed interclavicles in the early sauropodomorph Massospondylus or the theropods Oviraptor and Velociraptor were later reinterpreted as clavicles or furculae. Independent from their identification, the existence of the reported bones has both phylogenetic and functional significance. Their presence in non-neosauropod Eusauropoda and Flagellicaudata and probable absence in rebbachisaurs and Titanosauriformes shows a clear character polarity. This implicates that the ossification of these bones can be considered plesiomorphic for Sauropoda. The proposed presence of interclavicles in sauropods may give further support to a recent study, which finds a homology of the avian furcula with the interclavicle to be equally parsimonious to the traditional theory that furcula were formed by the fusion of the clavicles. Functional implications are the stabilizing of the chest region, which coincides with the development of elongated cervical and caudal vertebral columns or the use of the tail as defensive weapon. The loss of ossified chest bones coincides with more widely spaced limbs, and the evolution of a wide-gauge locomotor style.
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Affiliation(s)
- Emanuel Tschopp
- CICEGe, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal.
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Miescher K, Scholz C, Tschopp E. The activation of female sex hormones: Oestrone and its esters. The output of activity and efficiency coefficient. Biochem J 2006; 32:141-8. [PMID: 16746588 PMCID: PMC1264003 DOI: 10.1042/bj0320141] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Meystre C, Tschopp E, Wettstein A. Über Steroide. 81. Mitteilung. Über 11-Dehydro-Progesteron, das wirksamste Gestagen. Helv Chim Acta 2004; 31:1463-9. [DOI: 10.1002/hlca.19480310604] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Meier R, Tschopp E. Die Abh�ngigkeit der Gr��e und Form der Zeit-Wirkungsfl�che von Dosis und Resorptionsgr��e bei Testosteronestern. Naunyn Schmiedebergs Arch Pharmacol 1955. [DOI: 10.1007/bf00247428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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31
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